title: [Reproducibility and accuracy in the morphometric and mechanical quantification of trabecular bone from 3 Tesla magnetic resonance images].
abstract: OBJECTIVE
  We used an animal model to analyze the reproducibility and accuracy of certain biomarkers of bone image quality in comparison to a gold standard of computed microtomography (μCT).
  
  
  METHODS
  We used magnetic resonance (MR) imaging and μCT to study the metaphyses of 5 sheep tibiae. The MR images (3 Teslas) were acquired with a T1-weighted gradient echo sequence and an isotropic spatial resolution of 180μm. The μCT images were acquired using a scanner with a spatial resolution of 7.5μm isotropic voxels. In the preparation of the images, we applied equalization, interpolation, and thresholding algorithms. In the quantitative analysis, we calculated the percentage of bone volume (BV/TV), the trabecular thickness (Tb.Th), the trabecular separation (Tb.Sp), the trabecular index (Tb.N), the 2D fractal dimension (D(2D)), the 3D fractal dimension (D(3D)), and the elastic module in the three spatial directions (Ex, Ey and Ez).
  
  
  RESULTS
  The morphometric and mechanical quantification of trabecular bone by MR was very reproducible, with percentages of variation below 9% for all the parameters. Its accuracy compared to the gold standard (μCT) was high, with errors less than 15% for BV/TV, D(2D), D(3D), and E(app)x, E(app)y and E(app)z.
  
  
  CONCLUSIONS
  Our experimental results in animals confirm that the parameters of BV/TV, D(2D), D(3D), and E(app)x, E(app)y and E(app)z obtained by MR have excellent reproducibility and accuracy and can be used as imaging biomarkers for the quality of trabecular bone.
authors.affiliation: Servicio de Radiología, Hospital Quirón de Valencia, Valencia, España. Electronic address: angel.alberich@quiron.es.
authors.forename: A
authors.initials: A
authors.lastname: Alberich-Bayarri
authors.affiliation: Servicio de Radiología, Hospital Quirón de Valencia, Valencia, España; Unidad de Radiología, Departamento de Medicina, Universitat de València, Valencia, España.
authors.forename: L
authors.initials: L
authors.lastname: Martí-Bonmatí
authors.affiliation: Servicio de Radiología, Hospital Quirón de Valencia, Valencia, España.
authors.forename: R
authors.initials: R
authors.lastname: Sanz-Requena
authors.affiliation: RM Clinical Science, Philips Cuidado de la Salud, Madrid, España.
authors.forename: J
authors.initials: J
authors.lastname: Sánchez-González
authors.affiliation: Servicio de Radiología, Hospital Quirón de Valencia, Valencia, España.
authors.forename: V
authors.initials: V
authors.lastname: Hervás Briz
authors.affiliation: Servicio de Radiología, Hospital Quirón de Valencia, Valencia, España; Centro de Investigación Biomédica En Red de Salud Mental (CIBERSAM), Valencia, España.
authors.forename: G
authors.initials: G
authors.lastname: García-Martí
authors.affiliation: Instituto de Investigación e Ingeniería de Aragón (I3A), Universidad de Zaragoza, Zaragoza, España.
authors.forename: M Á
authors.initials: MÁ
authors.lastname: Pérez
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D015203:Reproducibility of Results; D012756:Sheep
keywords: Biomarcadores de imagen; Bones; Huesos; Imaging biomarkers; Magmetic resonance; Malla trabecular; Osteoporosis; Reproducibilidad de resultados; Reproducibility of results; Resonancia magnética; Trabecular meshwork